Gas stations run out of high-grade gas

On top of a price increase in gas and diesel Friday morning, a number of gas stations in the Halifax area say they've run out of premium and supreme gas after drivers flocked to the pumps Thursday night.

Some stations have posted signs saying they are also out of mid-grade fuel because it uses high-grade fuel in its mixture.

The price of gas increased by over 6.4 cents.

Oil industry officials say there's no connection between the price hike and the fact that stations cannot buy premium or mid-grade gasoline.

Imperial oil calls the shortage a "blending problem" at the oil refinery in Dartmouth, where they couldn't turn crude into premium quality gas.

"The refinery is operating normally and we are producing all other products including regular gasoline," said Pius Rolheiser, a spokesman for Imperial Oil in Calgary.

A refinery typically heats up crude oil, to break down the long-chain molecules into shorter molecules that can be burned more efficiently.

The outcome of the process often depends on the chemical make-up of the crude oil that it starts with, and some crude can be more difficult to process than the rest.

And just like baking a cake, the recipe doesn't always turn out.

Imperial says it's trying to make modifications to resolve problems with its latest batch of premium fuel.

Rolheiser says Imperial hopes to have new supplies delivered to gas pumps by Sunday.